Study of 2-bit Antenna–Filter–Antenna Elements for Reconfigurable Millimeter-Wave Lens Arrays

Abstract

This paper presents a new reconfigurable antenna-filter-antenna (AFA) element based on slot antennas and switchable resonators. This reconfigurable AFA can operate in four modes of operation as a three-or four-pole filter, and yields a 2-bit variable phase delay. As a result, the multimode AFA can be used as the building block of 2-bit adaptive lens arrays. This paper details design, modeling, and miniaturization of the reconfigurable AFA, and demonstrates its performance through preconfigured prototypes. The proposed AFA has a loss of 1.4-1.6 dB measured at 32 GHz in both three-and four-pole filter modes, and exhibits a frequency response that is almost insensitive to the angle of incidence. Several proof-of-concept fixed lens arrays have been also fabricated for output beams scanned to 0 , 15 , 30 , 45 , and 60 in the -and -plane. The measurement results show that the output beam can be scanned to 60 in both principle planes, with a worst case sidelobe level of less than 11 dB and a scan loss that hardly exceeds the theoretical limit.Index Terms-Antenna-filter-antennas, beam steering, frequency-selective surface (FSS), microelectromechanical systems (MEMS) antennas, phase shifters, reconfigurable antennas.

On aperture coupling based compact system of lens enhanced phased array

“…Consequently, four types of AFA elements can be combined to implement the desired LA phase delay profile with two bits of accuracy. Though the phase relationships are exact only at the center frequency, simulations predict that they remain within 10% of the nominal values for entire passbands of the 3-pole and 4-pole filters [6].…”

“…An incident wave with layer proper polarization is received by the top slot antenna in the input side, passes through a half-wave stripline resonator, and then reradiates from the bottom slot antenna on the output side with orthogonal polarization. The coupling between the slot antennas and stripline resonator takes place at the open ends of the resonator and can be controlled by the length of the portion of the stripline that is exposed to the electric field in the slots and the distance of the coupling region from the center of the slots as well [6]. Fig.…”

“…Due to the higher efficiency of slot antennas and higher Q of stripline resonators, such structures are capable of producing very low-loss AFA elements. This type of AFA element has been demonstrated for implementing fixed lens arrays [6]. This paper presents the lens array design with the modified phase delay profile implemented by using this kind of AFA elements for application in a 60GHz compact LEPA system.…”

Bandpass Antenna-Filter-Antenna Arrays for Millimeter-Wave Filtering Applications

“…1. Each AFA module is composed of receive antenna, a nonradiating resonant structure, and a transmit antenna [8][9][10][11][12]. Although the frequency characteristics of the antenna set the limit on the transmission bandwidth of these modules, a more general category of filtering shapes can be synthesized using this method.…”

Free‐Standing Metasurfaces for High‐Efficiency Transmitarrays for Controlling Terahertz Waves

“…Previously, it had also been reported that beam scanning can be realized by adding active component to each element of a transmitarray. [11][12][13][14][15] However, all the aforementioned approaches were reported to manipulate the electromagnetic (EM) waves through the gradient phase accumulation along a relatively long path in natural material or metamaterial. Several techniques have been adopted by different groups to effectively reduce the thickness of transmitarrays, such as by using large refractive-index materials.…”